同时上传参数及图片到 Web Api

方法一:利用 FormData

JS:

        function uploadFileAndParam() {
            var url = "http://localhost:42561/api/upload/UploadPost";
            /*
            FormData 对象就是模拟一个Form表单格式的数据,以二进制的方式提交,等同于 Form 表单 设置 enctype="multipart/form-data".
            由于 ajax 请求默认 contentType:"application/x-www-form-urlencoded" (这也是 Form 表单 enctype 的默认值)
            所以需要设置 
            contentType: false
            processData: false
            */
            var data = new FormData($("#myForm")[0]);//参数是JS对象,而 $("#myForm") 是JQ对象,并且是数组,所以需要加[0]
            data.append("sex", 1);//追加数据
            data.delete("name");//删除数据
            var id = data.get("id");//获取数据
            //还有 has(),getAll(),forEach() 等方法.

            $.ajax({
                url: url,
                data: data,
                type: "post",
                cache: false,//不缓存,暂时不明白为什么 FormData 对象提交,都要设置这个
                contentType: false,//告诉JQ, 不要设置 ContentType 请求头
                processData: false,//告诉JQ, 不要处理发送的数据
                success: function () { }
            });
        }

HTML:

    <div>
        <span>测试同时Post参数及文件</span><br />
        <form action="http://localhost:42561/api/upload/UploadPost" method="post" id="myForm">
            <input type="text" name="id" value="11" />
            <input type="text" name="name" value="中1&1文" />
            <input type="text" name="age" value="22" />
            <input type="file" name="myFile" />
            <input type="submit" value="submit提交" />
            <input type="button" value="button提交" onclick="uploadFileAndParam()" />
        </form>
    </div>

方法二:原生Form表单提交

        <form id="myForm6" enctype="multipart/form-data" method="post" action="http://*****">
            <input type="text" name="id" value="35" />
            <input type="text" name="name" value="wjire" />
            <input type="file" name="myFile" />
            <input type="submit" value="submit提交" />
        </form>

后台 Web Api 接收

public async Task<HttpResponseMessage> UploadPost() {
            var request = HttpContext.Current.Request;
            var id = request.Form["id"];
            var name = request.Form["name"];
            var age = request.Form["age"];
            var files = HttpContext.Current.Request.Files;
            var path = HttpContext.Current.Server.MapPath("/img/");
            if (files.Count > 0) {
                foreach (string file in files) {
                    var img = files[file];
                    if (img?.ContentLength > 0) {
                        var fileName = img.FileName;
                        await Task.Run(() => img.SaveAs(path + fileName));
                    }
                }
                return new HttpResponseMessage(HttpStatusCode.OK)
                {
                     Content = new StringContent("成功@!!!!!")
                };
            } else {
                var stream = request.InputStream;
                if (stream.Length > 0) {
                    var bytes = new byte[stream.Length];
                    stream.Read(bytes, 0, bytes.Length);
                }
            }
            return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "没有文件");
        }